ash from the fire place - Knowledgebase Question

roslyn hts, Ne
Question by ipekurian
January 21, 2011
I have lots ashes(woodburning) from fire place.how can i use this as fertlizer ?


Image
Answer from NGA
January 21, 2011

0

Wood ash has some value as a fertilizer, depending upon the type of wood you burned in your fireplace. Generally, wood ash contains less than 10 percent potash, 1 percent phosphate and trace amounts of micro-nutrients such as iron, manganese, boron, copper and zinc. Trace amounts of heavy metals such as lead, cadmium, nickel and chromium also may be present, but wood ash does not contain nitrogen.

The largest component of wood ash (about 25 percent) is calcium carbonate, a common liming material that increases soil alkalinity. Wood ash has a very fine particle size, so it reacts rapidly and completely in the soil. Although small amounts of nutrients are applied with wood ash, the main effect is that of a liming agent.

Increasing the alkalinity of the soil affects plant nutrition so use caution when applying wood as to your garden. Nutrients are most readily available to plants when the soil is slightly acidic. As soil alkalinity increases and the pH rises above 7.0, nutrients such as phosphorus, iron, boron, manganese, copper, zinc and potassium become chemically tied to the soil and less available for plant use.

Applying small amounts of wood ash to most soils will not adversely affect your garden, and the ash does help replenish some nutrients. But because wood ash increases soil pH, adding large amounts can do more harm than good. Keep in mind that wood ash that has been exposed to the weather, particularly rainfall, has lost a lot of its potency, including nutrients.

Specific recommendations for the use of wood ash in the garden are difficult to make because soil composition and reaction varies from garden to garden. Acidic soils (pH less than 5.5) will likely be improved by wood ash addition. Soils that are slightly acidic (pH 6.0 to 6.5) probably won't be harmed by the application of 20 pounds per 100 square feet annually, if the ash is worked into the soil about 6 inches or so. However, if your soil is neutral or alkaline (pH 7.0 or greater), find another way to dispose of wood ash. If you don't know your soil's acidity or alkalinity level, have it tested before apply wood ash. Hope this information is helpful!

You must be signed in before you can post questions or answers. Click here to join!

« Return to the Garden Knowledgebase Homepage

Member Login:

Username:

Password:

[ Join now ]

Today's site banner is by plantmanager and is called "Blue My Mind"